Ok liberals explain why you defend the 1st ammendment but not the 2nd?

.....or why it's a person's choice to murder a child but not to kill a full grown human who is trying to kill you? My loathing meter red-lined when they lit those buildings up in New York in celebration of murder. (and they say they're not 'fascists) They want to put Tutankhamun and King Herod to shame, and they've already beaten Hitler and the holocaust game.